Kirsche stuff is a bit complicated but I'll try to summarize it. Everything that I know is from her threads in thevirtualasylum.com (vtuber """kiwifarms"""), I can't archive everything now due to me being on mobile rn.
First a bit of info about kirsche, she's a indie vtuber that's you could say that she's political due she doing streams about current meta(political or not) on fridays(Tangent Friday) and she's a vtuber whose political side leans more to the right. A lot of inspiration to her is people like old Sargon, Tim Pool and other political youtubers, so you can guess that she has unpopular views to the mainstream society.
Now the dev part. Kirsche has a channel on her discord(nsfw) where you could join in the past just by selecting a role on the roles channel. That channel was the political channel one on her discord, because of the stuff above, she attracts a lot of /pol/ and right people from Twitter and DFD(Dev mod) was one of them.
After the mod joined, he aparently watched a few streams of her and then introduced her to dev, after the introduction, dev showed up on one of her streams, discord and tried to be a fat fuck as always there but because a lot of people there knows him, they tried to do the possible and impossible to remove him from there because he would try to cancel and fuck with kirsche.
Kirsche ignored then and talked with dev a lot and when she discovered how shit he was she removed him from her discord, with that ban, his mod DFD began to shit talk about kirsche and tried to cancel her on Twitter, after that dfd showed that he archived all channel messages from her discord, after a few weeks it got leaked(due inside job) that dev was planning a video on her but the backlash of it was so big that it never happened